I think you are right that the endgame might not be for you, but I second trying pvp because it's completely reactionary instead of having mechanics to do. There are plenty of other fun things to do in the game like chocobo racing, triple triad, doman mahjong, verminion, gates, potd/hoh, roleplaying, crafting/gathering, blue mage, hunts, but these are usually either pugged or done solo and I think you wanted it to be things done with a static.

The easiest rotations would be that of healers who just spam a single button for damage and refresh a dot sometimes. Blue Mages can form a static and do endgame content together and there is some flexibility in which actions you can use, so you could create your own rotation that works for you even if it's not the best one.